The present invention relates to methods and compositions for the treatment of cancer.
One drug that has proven effective in the treatment of certain tumors is cisplatin (cis-dichlorodiamine-platinum(II)). However, cisplatin has certain disadvantages. For example, its use in some circumstances is limited by its toxicity to the patient, especially its nephrotoxicity. As another example, tumors sometimes develop resistance to cisplatin.
In an effort to overcome the disadvantages of cisplatin, researchers have synthesized and tested various other platinum complexes as potential antitumor agents. One such compound is dichloro(1,2-diaminocyclohexane) platinum(II) (referred to in the remainder of this patent as “DACH-Pt—Cl2”). However, this compound has very low solubility in water, making it impractical for formulation and administration in aqueous solution. Further, although various platinum complexes have been formulated in liposomes in the past, a liposomal formulation of DACH-Pt—Cl2 has not been developed because that complex is insoluble in most organic solvents. Although it has good solubility in dimethylformamide, that solvent has a very high boiling point, therefore making it impossible or impractical to prepare a liposomal formulation of DACH-Pt—Cl2 using standard evaporation methods.
Other platinum-based antitumor drugs, such as cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum (II) (NDDP) have been prepared and tested as antitumor agents. However, a need still exists for improved antitumor drug formulations that have good antitumor activity, low toxicity to non-cancerous cells in a patient, and desirable storage characteristics.